Wild Red-legged Partridges Research Articles

A non-invasive method to monitor farmland bird exposure to triazole fungicides

The treatment of seeds with pesticides is an extended practice in current agriculture. There is a high risk of exposure in granivorous birds, such as the red-legged partridge (Alectoris rufa), that can consume those seeds remaining on the surface during sowing. Fungicide exposure could in turn affect bird reproductive capacity. To better understand to what extent triazole fungicides are a threat to granivorous birds, we need an easy and reliable method to quantify field exposure. In this study, we tested a novel non-invasive method to detect the presence of triazole fungicide residues in farmland bird faeces. We experimentally exposed captive red-legged partridges to validate the method, and then applied it in a real scenario to assess exposure of wild partridges. We exposed adult partridges to seeds treated with two formulations containing triazole fungicides as active ingredients: Vincit®Minima (flutriafol 2.5%) and Raxil®Plus (prothioconazole 25% and tebuconazole 15%). We collected two types of faeces (caecal and rectal samples) immediately after exposure and 7 days later and quantified the concentrations of the three triazoles and their common metabolite (1,2,4-triazole). The three active ingredients and 1,2,4-triazole were only detected in faeces collected immediately after exposure. Triazole fungicide detection rates in rectal stool were 28.6%, 73.3% and 80% for flutriafol, prothioconazole and tebuconazole, respectively. In caecal samples, detection rates were 40%, 93.3% and 33.3%, respectively. 1,2,4-triazole was detected in 53% of rectal samples. For an applied use of the method in the field, we collected 43 faecal samples from wild red-legged partridges during autumn cereal seed sowing and found detectable levels of tebuconazole in 18.6% of the analysed wild partridges. The results of the experiment were then used to estimate actual exposure levels from this prevalence value found in wild birds. Our study shows that faecal analysis can be a useful tool to assess farmland bird exposure to triazole fungicides, when samples are fresh and the method has been validated for the detection of target molecules.

Bird exposure to fungicides through the consumption of treated seeds: A study of wild red-legged partridges in central Spain

Sown seeds are a key component of many farmland birds’ diets due to natural food shortages in autumn and winter. Because these seeds are often treated with pesticides, their ingestion by birds can result in toxic effects. For risk assessment, data on treated seed toxicity should be combined with information about exposure risk for wild birds and the factors that modulate it. We characterized the exposure of red-legged partridges to pesticide-treated seeds through the analysis of digestive contents of birds shot by hunters (n = 194) in an agricultural region in central Spain. We measured the contribution of sown seeds to the partridges' diet and how it related to pesticide exposure. Moreover, we evaluated the influence of landscape composition on the intake of sown seeds and pesticides by partridges. During peak sowing time, seeds constituted half (50.7%) of the fresh biomass ingested by partridges, which consumed mostly winter cereal seeds (42.3% of biomass). Residues of seven fungicides and one insecticide (active ingredients) were detected in 33.0% of birds. The presence of pesticides in digestive contents was linked to the ingestion of cereal sown seeds. Moreover, dietary exposure of birds to pesticides was modulated by landscape characteristics, being lower in areas with heterogeneous landscapes, greater habitat mosaic and more natural vegetation. The estimated dietary intake of pesticides resulting from our field observations, in combination with experimental data on pesticide toxicity, raise concerns about the risks that pesticide-treated cereal seeds pose to granivorous bird populations. Our results highlight the importance of farming landscape composition and diversification, which should be considered as a priority in the agricultural policy to mitigate pesticide risks to farmland birds through the consumption of treated seeds.

Pathology of Trombiculosis caused by Neoschoengastia simonovichi in Wild Red-Legged Partridges (Alectoris rufa)

Lesions caused by trombiculid mite larvae ('chiggers') in birds have been inadequately described. A juvenile red-legged partridge (Alectoris rufa) presented with multifocal, crater-like lesions of necrotizing dermatitis, which often contained multiple orange mites. Microscopically, there was a nodular necrotizing and pyogranulomatous dermatitis with occasional intralesional arthropods. Histologically, the mites were readily identified by the presence of stylostomes within the necrotic areas. Morphological and morphometrical studies on isolated mites identified them as Neoschoengastia (Hypogastia) simonovichi. This is the first report of N. simonovichi as an aetiological agent of severe trombiculosis in wild birds in Western Europe. Infestation with this parasite requires further study to understand its role in animal and human trombiculosis and its potential role as a vector of infectious, including zoonotic, agents.

Body proportions for the facilitation of walking, running and flying: the case of partridges

BackgroundPredation is one of the most important natural selection forces. Prey species can optimize feeding behavior and escape from predators based on mobility conditioned by body proportions. With age, mobility capacity increases and individuals are more efficient in finding resources and safety (e.g., food and refuge). Birds’ mobility is driven by the dimensions, of the head and torso, as well as the extremities and flight feathers. To assess the relationship between body traits and to understand how body proportions are organized in wild Red-legged partridges (Alectoris rufa), we used biometric data from nearly 14,000 individuals, obtained during a long-term study (1988–2011) on a wild population.ResultsWe used GLMs and regressions to model the relationship between body mass and the size of body parts. We found that wing length was the morphological part best explained by other body trait measures. Wing length models were better predictors in juveniles than in adults and in females than in males. Wing length and feather length, mass and total length are the most strongly related parts; mass and wing length, total length and feather length are moderately related. The association between mass and wing length is intermediated by feather length and total length.ConclusionsSocial inclusion, feeding and predator evasion may be affected by body structure intermediated by mobility and health. Our results suggest that proportions of the body, extremities and flight feathers drive mobility which is intimately associated with ecology, biological efficiency, health and physical optimization. Our findings showed that wing size was strongly allied to other body part measurements, enhancing the importance of body structure conformation for flight. Our study highlights the scaled relationship of body structure among age-sex classes and its relevance to social cohesion, flock movement and the balance between predation and starvation.

The fractal dimension of a conspicuous ornament varies with mating status and shows assortative mating in wild red-legged partridges (Alectoris rufa).

Complex body designs, such as plumage ornaments in birds, can be described by fractal geometry. These complex patterns could have a role as visual signals during courtship and social interactions, but an empirical validation in the wild is currently lacking. Here, we investigated whether the fractal dimension (FD) of a complex plumage pattern displayed by red-legged partridges Alectoris rufa could function as a potential sexual signal. We captured wild birds early in the breeding season and tested if mated and unmated birds differed in the FD of their conspicuous melanin-based black bib. We also tested if the FD of the black bib was correlated within the pair, looking for evidence of assortative mating based on the expression of this trait. We simultaneously assessed similar effects in other ornamental traits (black bib size, white throat patch and black flank band surface, redness of the eye rings and bill). Mated birds showed higher black bib FD values than unmated ones. Mated males, but not females, also displayed a larger black bib. Moreover, the black bib FD (but not the trait size) and the white throat patch surface showed assortative mating. Finally, females with higher black bib FD showed smaller black flank band surface, suggesting a trade-off in the expression of the two melanin-pigmented plumage traits. This provides unique and novel indication for the shape complexity of a pigmented trait, here described by its fractal dimension, to be potentially under sexual selection in a wild animal.

The effects of scaling on age, sex and size relationships in Red-legged Partridges

Wild birds differ in size according to their age and sex, adult birds being larger than juveniles. In the galliforms, males are larger than females, in contrast to some groups, such as the raptors, in which the females are larger. Size generally influences the rank hierarchy within a group of birds, although the age, sex, temperament and behaviour of an individual may override its size related rank order. The scaled size of birds according to age and sex affects their physiology and behaviour. Precise details of body-size differences by age and sex are poorly known in most partridge species. We measured 13,814 wild partridges in a homogenous population over 14 years of study to evaluate size differences within a uniform habitat and population management regime. We show that wild Red-legged Partridges have scaled mass, and body- and wing-lengths consistent with age/sex classes. Power functions between mass and body-length (as a proxy for walking efficiency), and between mass and wing-length (for flight efficiency) differ between juvenile females and males, and adult females and males. We discuss these findings and their physiological, behavioural and ecological implications.

Feathers for escape: the transition from juvenile to adult in red-legged partridges (Alectoris rufa)

Almost all birds use their fight feathers as a means of escaping predators, and their specific design is adapted to their individual circumstances. For example, Galliform birds use a fast, explosive, noisy take-off to startle a predator. Their legs, wings and feathers must work together to create a strong propulsive force and loud, rhythmic sound. Partridges in a group initiate escape simultaneously, even though individuals in the flock differ in size and experience, as well as in age and sex resulting in feathers that differ in length and shape. In a long-term study, we measured 13814 wild red-legged partridges (Alectoris rufa) to understand how variation in feather proportions and morphometrics between the age–sex classes relate to their escape abilities. We devised two new indexes to quantify the aerodynamic differences between age–sex classes. Our approach synthesizes the understanding of bird take-flight mechanics, feather proportions and the aerodynamic properties of wing tips to show how differences in feather length and tip shape characterize age–sex classes. Our findings suggest that the density, stiffness, permeability, size and shape of the distal primary feathers and wing tips can explain aerodynamic differences between individuals and the efficiency of groups in escape situations.

Nodular TROMBICULIOSIS Caused by Neoschoengastia simonovichi in a Group of Wild Red-Legged Partridges (Alectoris rufa)

Nodular TROMBICULIOSIS Caused by Neoschoengastia simonovichi in a Group of Wild Red-Legged Partridges (Alectoris rufa)

Do Wild Red-Legged Partridges (Alectoris rufa) Use Feeders? An Investigation of their Feeding Patterns using Camera Trapping

This paper explores feeding patterns of wild Red-legged Partridges ( Alectoris rufa) at artificial feeders, a common management action for game species. Feeders were studied during two consecutive periods from October 2009 to May 2011 in an agricultural area of northwest Spain. Camera trapping was used in order to assess climatic effects on weekly feeding patterns, investigate the influence of shrub cover on feed-site selection and evaluate behavioural patterns displayed when using feeders. Red-legged partridges used feeders throughout the study period, but particularly from December to February. No significant correlations were observed between the weekly number of photographs and climate conditions. A bimodal circadian feeding pattern was observed during daylight hours with peaks of activity in the morning and evening while, in central hours, the feeding visits decreased. We observed significant differences in the number of partridges photographed during the feeding visits along the study period. The use of feeders was not influenced by the presence of surrounding vegetation nor type of feeder. The behavioural analysis classified partridges in five different categories: feeding (33.5 and 32.3% for each period respectively), vigilance (26.8 and 30.7%), moving/unknown (25.9 and 20.6%), pecking/ dusting (11.2 and 15%) and other behaviours (2.8 and 1.8%). The percentage of vigilant birds photographed at feeders was not related to the covey size. This study demonstrates the use of the feeders by Red-legged Partridges but does not prove the potential benefits.

Astaxanthin and papilioerythrinone in the skin of birds: a chromatic convergence of two metabolic routes with different precursors?

Carotenoids are organic pigments involved in several important physiological functions and may serve as indicators of individual quality in animals. These pigments are only obtained by animals from the diet, but they can be later transformed into other carotenoids by specific enzymatic reactions. The diet of farm-reared and probably wild red-legged partridges (Alectoris rufa) is mainly based on cereals that contain high levels of lutein and zeaxanthin. These two carotenoids are also predominant in internal tissues and blood of red-legged partridges. However, in their integuments, astaxanthin and papilioerythrinone (the last one identified in this work) are mainly present in their free form and esterified with fatty acids. According to available literature about carotenoid metabolism in animals, we propose that astaxanthin (λ max = 478 nm) and papilioerythrinone (λ max = 452-478 nm) are the result of a chromatic convergence of the transformation of dietary zeaxanthin and lutein, respectively. Moreover, the results obtained in this work provide the first identification by liquid chromatography coupled to accurate mass quadrupole time-of-flight mass spectrometer system of papilioerythrinone (m/z 581.3989 [M + H](+)) in the skin (i.e., not feathers) of a vertebrate. Astaxanthin and papilioerythrinone are very close in terms of chemical structure and coloration, and the combination of these two keto-carotenoids is responsible for the red color of the ornaments in red-legged partridges.

La perdiz roja (Alectoris rufa) en España: especie cinegética y amenazada

Vinuela, J., Casas, F., Diaz-Fernandez, S., Delibes-Mateos, M., Mougeot, F., Arroyo, B. (2013). The red-legged partridge ( Alectoris rufa ) in Spain: a threatened game species. Ecosistemas 22(2):6-12. Doi.: 10.7818/ECOS.2013.22-2.02 We review scientific knowledge on red-legged partridge ecology and management, focusing on recent studies. Red-legged partridge is a greatly valued game species, whose conservation status has been, and probably still is, poor. In small-game hunting estates, great efforts are devoted to red-legged partridge management, but many practices are applied without knowing their real consequences for partridge populations. Reviewed studies show that the most successful management options to increase the abundance of the species, allowing a sustainable harvest, would include an adequate adjustment of annual harvest to partridge abundance, appropriate habitat management promoting the presence of natural vegetation within the farmland matrix and field edges, and water and food supplementation. Information about the efficacy of predator control to increase red-legged partridge abundance is inconclusive. Releases of farm-reared partridges are putting at risk the genetic integrity of the species. Furthermore, when few partridges are released, releases do not increase annual harvest or estate profitability, and negatively affect the productivity of wild red-legged partridges. Despite leisure and economic movement generated by red-legged partridge hunting, inadequate management is currently reducing the potential benefits of this activity.

Use of an AG Microsatellite to Characterise Alectoris Species

The red-legged partridge ( Alectoris rufa) is normally found in the Iberian Peninsula, southern France and some points of northern Italy and southern England. A number of factors have drastically reduced the number of wild red-legged partridges in these areas. It is necessary to know their genetic situation and to identify different populations and species. Microsatellite markers are very effective genetic markers. In order to identify microsatellite markers in this species to gain genetic knowledge of their populations, DNA was cleaved partially with AluI and ligated in plasmid pSMART; this was inserted in Escherichia coli to obtain a whole genome library. This library was screened by amplifying with the polymerase chain reaction and then sequencing the A. rufa DNA in plasmids isolated from colonies selected at random. Some of the sequenced PCR products were found to contain possible microsatellite sequences and two of these were used to characterise four different species of Alectoris. One of these sequences (GTTTT) was always found to be repeated three times but the number of repeats of the second one (AG) was found to vary between species. Therefore, the (AG)n microsatellite may be a good candidate to distinguish between species of the genre Alectoris.

Flaviviruses in Game Birds, Southern Spain, 2011–2012

Flaviviruses in Game Birds, Southern Spain, 2011–2012

Phenotypic differences in body size, body condition and circulating carotenoids between hybrid and “pure” red-legged partridges (Alectoris rufa) in the wild

In the last decades, the release of large numbers of farmed-reared birds became a widespread management practice for game species. The red-legged partridge (Alectoris rufa) is a quarry species with a high economic impact in rural areas of southwest Europe. In order to increase productivity and produce heavier birds, farmed red-legged partridges have often been hybridized with Chukar partridges (A. chukar), although these species have allopatric distribution ranges. During restocking, hybrid birds may be released into wild populations and may subsequently successfully breed, thus threatening the genetic integrity of native A. rufa populations. In this study, we compared several phenotypic indicators (body size, body condition and physiological state) between “pure” and hybrid partridges in order to evaluate the possible consequences of A. chukar genetic introgression into A. rufa. For this purpose, we captured 115 wild red-legged partridges during the breeding seasons 2003–2005 in four game estates of central Spain. We observed a greater occurrence of hybrid A. rufa × A. chukar partridges nearby the sites where the release of farmed-birds took place. We also found that hybrid males were smaller and hybrid females had better body condition and lower plasma carotenoid concentration than pure partridges of the same sex. Low carotenoid levels in blood plasma might be a limitation for female reproduction (fewer carotenoids available for ornamentation or to allocate to eggs). Overall, our results showed a greater occurrence of hybrids near restocking areas and phenotypic differences between hybrids and “pure” partridge in the wild. Genetic controls of farm-reared partridges should be a key step to prevent the releases of hybrids and ensure the maintenance of the genetic integrity of wild red-legged partridge populations.

Harvest of red‐legged partridge in central Spain

A basic rule to attain sustainable use of harvested resources is to adjust take to availability. Populations of red-legged partridges in Spain have decreased in recent decades, and releases of farm-bred partridges to improve short-term availability are increasingly common. We used questionnaires and bird surveys to assess whether harvest was related to availability of wild partridges or intensity of farm-bred partridge releases. We studied 50 hunting estates, including 6 administratively labeled as intensive (with few numerical and temporal restrictions to releases). In addition, we considered hunting pressure (number of hunters × hunting days/km2) and habitat as explanatory variables in the analyses. In intensive estates, annual harvest was exclusively related to release intensity, indicating that in these estates hunting is detached from natural resources and approaches an industrial activity based on external inputs. In non-intensive estates, harvest was affected by wild stock availability, walked-up shooting pressure, and habitat (greater harvest in estates with more Mediterranean shrubland). In these estates, releases did not increase annual harvest, and can be considered an inefficient practice. Additionally, the relationship between abundance estimates and harvest disappeared in estates with low partridge abundance estimates, suggesting possibilities for overharvesting in a large proportion of estates. Increasing the abundance of wild red-legged partridge through techniques like habitat management, and improving the adjustment of harvest to availability, may be a good strategy to increase long-term harvest in non-intensive estates. Additionally, Government and managers must create ways to segregate and label the estates where only wild red-legged partridges are managed from those where releases are used, to reduce ecological costs of management decisions. © 2012 The Wildlife Society.

Water-site selection and behaviour of red-legged partridge Alectoris rufa evaluated using camera trapping

This paper explores watering patterns of wild red-legged partridges at water troughs (WT) during three consecutive summers on a farm-land area of Spain where drought periods are frequent. Camera trapping was used in order to assess climatic effects on weekly and daily watering patterns, investigate the influence of shrub cover on water-site selection, evaluate behavioural patterns displayed when using WT, and describe age and number of birds observed at WT. Red-legged partridges used WT throughout the study period, but significant use did not occur until August, decreasing dramatically in mid September, and ending in October. A circadian watering pattern was observed during daylight hours with most photographs taken from 08:00hours to 11:00hours (54.8%). Partridges displayed different behaviours (drinking, feeding/dusting, vigilance, moving/unknown), but patterns did not vary significantly throughout the day. WT were used mostly by adult birds with only 26.5% of photographs also depicting young partridges. WT selection was strongly influenced by the presence of surrounding vegetation as partridges preferred troughs with shrub cover. We also found a significant negative relationship (P<0.05) between the percentage of vigilant birds and covey size at water sources with shrub cover. Given the high predation rates observed in this species, security risk is likely an important factor involved in water-site selection.

Fitness consequences of anthropogenic hybridization in wild red-legged partridge (Alectoris rufa, Phasianidae) populations

Hybridization is a widespread phenomenon, which plays crucial roles in the speciation of living beings. However, unnatural mixing of historically isolated taxa due to human-related activities has increased in recent decades, favouring levels of hybridization and introgression that can have important implications for conservation. The wild red-legged partridge (Alectoris rufa, Phasianidae) populations have recently declined and the releases of farm-reared partridges have become a widespread management strategy. The native range of the red-legged is limited to the south-west of Europe (from Italy to Portugal). This species does not breed in sympatry with the chukar partridge (A. chukar), whose range is Eurasian (from Turkey to China). However, red-legged partridges have often been hybridized with chukar partridges to increase the productivity of farmed birds, and game releases may have spread hybrid birds into the wild. In this study, we investigated the fitness (survival and breeding) differences between hybrid and “pure” red-legged partridges in a wild population located in central Spain. Incubation probability was similar in hybrids and “pure” partridges. Hybrid females laid larger clutches than “pure” ones, but hatching success did not differ between hybrid and “pure” partridges. Hybrid birds had lower survival rate than “pure” ones, mainly because of higher predation rates. Our results show that, despite lower survival, hybrid partridges breed in natural populations, so this could increase extinction risk of wild pure partridge populations, through releases of farmed hybrid birds. The consequences of continued releases could be of vital importance for the long term conservation of wild red-legged partridges.

Prevalence of Escherichia coli, Salmonella sp. and Campylobacter sp. in the intestinal flora of farm-reared, restocked and wild red-legged partridges (Alectoris rufa): is restocking using farm-reared birds a risk?

For hunting purposes, several millions of red-legged partridges (Alectoris rufa) are released each year in Spain, and these releases have the potential to introduce new parasites and disease into wild populations. We studied the prevalence of Escherichia coli, Campylobacter sp. and Salmonella sp. in the intestinal flora of red-legged partridges from three different husbandry groups: farm-reared, restocked and natural populations. Prevalence of E. coli was significantly higher in farm-reared (45%, p = 0.01) and restocked partridges (60%, p 0.05). The prevalence of Campylobacter sp. (23%, 100 out of 444) did not differ significantly between these three husbandry groups, and Salmonella sp. was only detected in a group of partridge chicks on one of the farms studied (0.9%, 5 out of 544). These results suggest that farm-reared and restocked partridges can act as carriers of these three enteropathogens and highlight a potential risk of transmission to natural populations via the releases of farm-reared partridges. However, future investigations are needed regarding the relation of the isolated bacteria with zoonotic strains and dissemination of antibiotic resistant microorganisms, especially E. coli, and to better evaluate the effect that these three enteropathogens have on partridge health and on the success of restocking with farm-reared birds.

Application of RAPD Methodology to Preserve the Purity of Wild Red-LeggedPartridges (Alectoris rufa, L.)

The red-legged partridge ( Alectoris rufa ) is a typical avian species of the Mediterranean area. Crossings of red-legged partridges with other Alectoris partridges have been done in order to increase the productivity of this species when captive bred. Restocking of hunting grounds with such hybrid partridges could damage the genetic heritage of the pure red-legged partridge in the wild. In order to avoid this problem RAPD-PCR has been developed to identify hybrid individuals. This methodology has been used to study wild red-legged partridges as well as partridges from different farms. RAPD analysis results in different patterns for different species. Hybrids can be detected among presumed red-legged partridges if they present a diagnostic band which characterises another species.

Mycobacterium avium disease in wild red-legged partridges (Alectoris rufa)

Three wild red-legged partridges (Alectoris rufa) from intensively managed hunting areas in Spain were received for necropsy. They showed granulomatous lesions in different parts of the body, mainly in liver and spleen. Microscope examination of the granulomas showed central caseous necrosis and large amounts of acid-fast bacilli, surrounded by epitheloid cells, giant cells, and lymphocytes. Attempts to isolate and culture the bacillus in Colestsos medium were unsuccessful, but the polymerase chain reaction technique revealed the presence of microorganisms belonging to the Mycobacterium avium complex in one of the partridges. This is the first report of avian tuberculosis in free-living red-legged partridges.